Bacterial biofilms and medical practice

A suboptimal environment with limited supply of nutrients leads to marked changes in the microbial features. Similar conditions exist also on some tissue surfaces of the human body and on biomedical devices implanted. The basic feature of this environmental adaptation is the adherence of microbes to some surfaces and production of abundant exopolysaccharides. Microbes embedded in this hydrated, mostly anionic polysaccharide matrix called biofilm. The biofilm acts not only by trapping the nutrient or oxygen molecules, but protects the microbes against phagocytic cells, antibodies, biocids, and antibiotics, too. This protected form is responsible for the special nature of normal flora, as well as for some clinical and therapeutic characters of several diseases. Microbes liberated from the biofilm, being in the so called planctonic phase. In cases where the biofilms have developed on biomedical devices such planctonic microbes may cause persistent or relapsing infections. These planctonic microbes can be eliminated by the host responses or by antibiotic treatments, while those in the biofilm cannot, thus serving as a source of further infections.     

Bacterial biofilms within the clinical setting: what healthcare professionals should know

Bacterial biofilm formation is the prevailing microbial lifestyle in natural and manmade environments and occurs on all surface types. Biofilm formation develops in several phases and is influenced by various parameters, both environmental and inherent to the attaching cell. Biofilms also serve as protective niches for particular pathogens when outside a host. Although it is accepted that biofilms are ubiquitous in nature, the significance of biofilms in clinical settings, especially with regard to their role in medical-related infections, is often underestimated. It has been found that several aspects of human pathogenesis within a clinical context are directly related to biofilm development. Various types of surfaces in clinical settings are prone to biofilm development and an increased risk of disease may be a direct consequence of their formation. This review describes the process of biofilm formation, highlights the importance of bacterial associations with surfaces in clinical settings and describes various methods for biofilm visualization and control.     

子宫内膜癌患者细菌感染与炎症因子的表达

目的探讨子宫内膜癌患者细菌感染及炎症因子白细胞介素-6(IL-6)、白细胞介素-11(IL-11)的表达,分析子宫内膜癌的发生与局部微环境中的炎症变化的关系,以揭示炎症在子宫内膜癌的发生及发展中的机制。方法选取医院2011年6月-2013年6月子宫内膜癌(研究组)与子宫肌瘤患者(对照组)各40例,采集宫颈分泌物及子宫内膜组织进行细菌培养,以免疫组化染色法检测子宫内膜组织中的IL-6、IL-11的表达。结果研究组患者宫颈分泌物、子宫内膜组织中细菌培养阳性率分别为40.00%、30.00%,高于对照组的15.00%、5.00%,两组细菌培养阳性率比较差异有统计学意义(P<0.05);子宫内膜癌患者低分化、中分化、高分化时子宫内膜组织细菌培养阳性率分别为25.00%、33.33%、28.57%,FIGO分期Ⅰ期、Ⅱ期时子宫内膜组织细菌培养阳性率分别为29.41%、33.33%,不同分化程度、分期子宫内膜组织中细菌培养阳性率比较差异无统计学意义;研究组子宫内膜组织中IL-6、IL-11阳性表达明显高于对照组,差异有统计学意义(P<0.05)。结论子宫内膜癌组织中细菌培养阳性率高于正常子宫内膜组织,炎症因子IL-6、IL-11阳性表达升高,提示感染及炎症因子可能参与了子宫内膜癌的发病过程。     

Bacterial infection in exacerbated COPD with changes in sputum characteristics

We examined the risk factors for bacterial exacerbation, defined as the presence of pathogenic bacteria in sputum, in 90 chronic obstructive pulmonary disease (COPD) patients with an exacerbation and changes in sputum characteristics. Smoking, alcohol, lung function, body mass index, medical visits and treatments were the independent variables assessed using multivariable logistic regression modelling (OR, 95% CI). A bacterial exacerbation was diagnosed in 39 (43.3%) of 90 patients. Bacterial exacerbations were more prevalent among current smokers (OR 3.77, 95% CI 1.17-12.12), in patients with poor compliance with inhalation therapy (OR 3.25, 95% CI 1.18-8.93) and with severe lung function impairment (FEV1 OR 0.96, 95% CI 0.93-1.00). Prior use of antibiotics was a risk factor for Pseudomonas aeruginosa infection (OR 6.06, 95% CI 1.29-28.44) and influenza vaccination appeared to have a protective effect against this infection (OR 0.15, 95% CI 0.03-0.67). We conclude that severe impairment of lung function, smoking and poor compliance with therapy are risk factors for bacterial infection in COPD, and P. aeruginosa should be suspected in patients who have been treated with antibiotics and in those not vaccinated against influenza.     

Fungal biofilms and drug resistance

Candida species, including the novel opportunistic pathogen Candida dubliniensis, are now emerging as major agents of nosocomial infections. Many such manifestations of infections associated with the formation of Candida biofilms include those occurring on devices such as indwelling intravascular catheters. Fungal biofilm-associated infections are frequently refractory to conventional therapy because of resistance to antimicrobial agents. This resistance could be in part due to the surface-induced upregulation of drug efflux pumps. Biofilm-associated Candida show uniform resistance to a wide spectrum of the currently available conventional antifungal agents, which implies that antimicrobial drugs that specifically target biofilm-associated infections are needed. The novel classes of antifungal agents, the lipid formulation of amphotericins, and the echinocandins have demonstrated unique antifungal activity against the resistant Candida biofilms, providing a breakthrough in the treatment of life-threatening invasive systemic mycoses. The use of drugs effective in combating biofilm-associated infections could lead to major developments in the treatment of fungal implant infections.     

医院内革兰阴性杆菌感染--细菌耐药与抗菌药物治疗

革兰阴性杆菌是医院内严重感染的常见病原菌.尤其在ICU常由耐药的铜绿假单胞菌、不动杆菌、肠杆菌科细菌及嗜麦芽窄食单胞菌引起感染,使重症患者的治疗十分困难[1].高娅文报告[2]长期住院的下呼吸道感染患者,铜绿假单胞菌占43.1%,不动杆菌占17.5%,肺炎克雷伯杆菌占13.1%,大肠埃希菌占11.5%,嗜麦芽窄食单胞菌占8.2%,阴沟肠杆菌占2.2%,其他占4.4%,但各单位的病原菌检出率可有很大差别[3].当分离到病原菌后要区分污染、定植与感染,对确定为感染的病原菌,才需及时选用合理的抗菌药物治疗,但要防止不必要的抗菌药物治疗诱发细菌耐药.     

老年患者泌尿系感染的病原菌分布及耐药性分析

目的探讨老年患者泌尿系感染的病原菌分布及耐药性,为临床合理应用抗菌药物提供科学依据。方法对来自临床科室的853份老年患者中段尿标本进行培养和分离,采用法国生物梅里埃公司VITEK-2 Compact全自动微生物分析仪进行病原菌鉴定和药敏试验。结果培养和分离出的病原菌以大肠埃希菌、肠球菌属和肺炎克雷伯菌最为多见,分别占39.7%、20.7%及7.7%;各病原菌对抗菌药物的耐药性差异较大,革兰阴性杆菌对碳青霉烯类药物无耐药性,革兰阳性球菌中,未发现对万古霉素耐药菌株,其他病原菌大多呈多药耐药。结论泌尿系感染是老年人常见疾病,病原菌对抗菌药物具有程度不等的耐药性和多药耐药,只有加强病原菌耐药性监测,用药敏试验来指导临床用药,才能科学有效的控制感染。     

Bacterial infection in relation to pain and irregular bleeding in women using IUD.

Pain and metrorrhagia in women using IUDs are often the reason for removing the IUD. In 54 women where the IUD was removed, uterine fluid for bacteriologic cultures was taken from the removed IUD. There was a correlation between positive cultures and symptoms of pain and metrorrhagia. Spotty bleeding caused by microtraumata and increased fibrinolytic activity of the IUD might thus consitute a substrate for bacterial invasion resulting in endometritis and in turn increased bleeding and pain. In 18 male consorts of females with positive cultures, asymptomatic bacteriospermia was found. Treatment offered alleviated symptoms. Removal of the IUD need thus not be necessary.     

重症监护病房小肺患者肺感染细菌及耐药情况

近年来,随着广谱抗生素的广泛应用,细菌耐药率不断上升.呼吸重症监护病房(RICU)尘肺患者由于其自身特点,如高龄、肺基础疾病多、病情重、住院时间长,医院感染高发.我们观察并分析了2001年1月至2003年7月本院RICU尘肺患者细菌感染及耐药的情况.     

Bacterial infection affects protein synthesis in primary lymphoid tissues and circulating lymphocytes of rats

Bacterial infection alters whole-body protein homeostasis. Although immune cells are of prime importance for host defense, the effect of sepsis on their protein synthesis rates is poorly documented. We analyzed protein synthesis rates in rat primary lymphoid tissues and circulating lymphocytes after infection. Male Sprague-Dawley rats were studied 1, 2, 6 or 10 d after an intravenous injection of live Escherichia coli. Control healthy rats consumed food ad libitum (d 0) or were pair-fed to infected rats. Protein synthesis was quantified using a flooding dose of L-(4,4,4-(2)H(3))valine. Sepsis induced a delayed increase in total blood leukocytes and a rapid and persistent inversion of the counts. Basal fractional rates of protein synthesis (ks) were 117, 73 and 29%/d in bone marrow, thymus and circulating lymphocytes, respectively. Pair-feeding strongly depressed the absolute protein synthesis rates (ASR) of bone marrow (d 2 and 10) and thymus (d 2-10). The infection per se increased bone marrow, thymus and circulating lymphocyte ks but at various postinfection times. It decreased bone marrow (d 1) and thymus (d 1 and 2) ASR but increased lymphocyte (d 2 and 10) and bone marrow (d 10) ASR. Our results reflect the deleterious effect of anorexia on primary lymphoid tissues. The host defense against bacterial infection exhibited time- and tissue-dependent modifications of protein synthesis, indicating that blood lymphocyte protein data are not representative of the immune system as a whole. Optimization of nutritional supports would be facilitated by including protein synthesis measurements of the immune system.     

Bacterial contamination of enteral feeds as a possible risk of nosocomial infection.

The degree of microbiological contamination in enteral diets was studied and the possible infectious complications that could arise in the patient after administration of an enteral feed were evaluated. Of the 208 diets studied, 56 (26.9%) were contaminated and 152 (73.1%) were sterile. Of the 56 contaminated diets, 11 could be used as delivered, but the other 45 required further modification. Of the patients who had received enteral feeding, 43 developed gastrointestinal symptoms in the first 24 h (fever, vomiting, abdominal pain and diarrhoea). Twenty-nine (67.4%) had received a contaminated diet and 14 (32.6%) an uncontaminated one. We conclude that contamination of enteral feeds may constitute a risk factor for nosocomial infection, and consider it necessary to carry out epidemiological surveillance in order to control the factors which may lead to contamination of enteral diets.     

Bacterial joint infections: a retrospective study for the source of the infection

Bacterial arthritis causes rapid damage of the affected joint. Knowledge of the source of the infection that leads to septic arthritis is necessary to judge possible preventive measurements. In this study we tried to detect the source of the infection in 77 episodes of bacterial arthritis in 73 patients admitted in the period 1976-1986. The source of infection was: a joint operation in 21, the skin in 15, the respiratory tract in 7, the genital tract in 8, others in 5, and unknown in 21. A skin infection was the source in patients suffering from rheumatoid arthritis. To our surprise in none of our cases was non-sterile surgery the cause of infection. Our results suggest that since perioperative joint infection is frequent, prevention of such infection may be meaningful. Skin infections are often the source of infection in rheumatoid arthritis, preventive measures are to be considered. Our results do not allow a judgment on the possible preventive measures for the other sources of infection detected or undetected. Administration of antibiotics during non-sterile surgery is not supported by the results of this study.     

Modulation of gut mucosal biofilms

Non-digestible inulin-type fructans, such as oligofructose and high-molecular-weight inulin, have been shown to have the ability to alter the intestinal microbiota composition in such a way that members of the microbial community, generally considered as health-promoting, are stimulated. Bifidobacteria and lactobacilli are the most frequently targeted organisms. Less information exists on effects of inulin-type fructans on the composition, metabolism and health-related significance of bacteria at or near the mucosa surface or in the mucus layer forming mucosa-associated biofilms. Using rats inoculated with a human faecal flora as an experimental model we have found that inulin-type fructans in the diet modulated the gut microbiota by stimulation of mucosa-associated bifidobacteria as well as by partial reduction of pathogenic Salmonella enterica subsp. enterica serovar Typhimurium and thereby benefit health. In addition to changes in mucosal biofilms, inulin-type fructans also induced changes in the colonic mucosa stimulating proliferation in the crypts, increasing the release of mucins, and altering the profile of mucin components in the goblet cells and epithelial mucus layer. These results indicate that inulin-type fructans may stabilise the gut mucosal barrier. Dietary supplementation with these prebiotics could offer a new approach to supporting the barrier function of the mucosa.     

全自动细菌生化鉴定分析仪与细菌微量生化管鉴定细菌的结果

目的:研究分析全自动细菌生化鉴定分析仪与细菌微量生化管鉴定细菌的结果。方法:2019年8月~2019年9月,选取本中心获取的50株肠杆菌科菌株为研究对象,其中大肠埃希菌23株,肺炎克雷伯菌12株,阴沟肠杆菌10株、不发酵和需氧革兰阴性杆菌5株,分别采用全自动细菌生化鉴定分析仪、细菌微量生化管进行鉴定,对比两种方法的鉴定结果。结果:全自动细菌生化鉴定分析仪的鉴定符合率与细菌微量生化管的鉴定符合率比较,不存在差异(P>0.05);两种鉴定方法鉴定大肠埃希菌、肺炎克雷伯菌、阴沟肠杆菌的准确率比较,不存在差异(P>0.05)。全自动细菌生化鉴定分析仪鉴定不发酵和需氧革兰阴性杆菌的准确率高于细菌微量生化管鉴定(P<0.05)。结论:全自动细菌生化鉴定分析仪与细菌微量生化管均可快速有效地鉴定常见肠杆菌科菌株,但在鉴定不发酵和需氧革兰阴性杆菌时,全自动细菌生化鉴定分析仪更具应用价值。     

胆道感染患者胆汁培养的菌谱调查及耐药性分析

目的 了解胆道感染病原菌种类及耐药性,为临床抗感染治疗提供依据.方法 对医院胆道感染患者胆汁中分离的216株细菌进行回顾性调查.结果 胆汁标本细菌阳性检出率为66.5％,居前5位的病原菌是大肠埃希菌、肺炎克雷伯菌、粪肠球菌、阴沟肠杆菌和凝固酶阴性葡萄球菌;除肠杆菌科细菌对亚胺培南和美罗培南100.0％敏感、革兰阳性球菌对万古霉素、替考拉宁100.0％敏感外,病原菌对其他常用抗菌药物均显示不同程度的耐药性.结论 临床应重视胆汁培养,按照药敏试验结果合理用药,以提高胆道感染临床治愈率.